1. Technical Field
The present invention relates to a method and apparatus for additive manufacturing of three-dimensional articles.
2. Description of Related Art
Freeform fabrication or additive manufacturing is a method for forming three-dimensional articles through successive fusion of chosen parts of powder layers applied to a worktable. A method and apparatus according to this technique is disclosed in US 2009/0152771.
Such an apparatus may comprise a work table on which said three-dimensional article is to be formed, a powder dispenser, arranged to lay down a thin layer of powder on the work table for the formation of a powder bed, a ray gun for delivering energy to the powder whereby fusion of the powder takes place, elements for control of the ray given off by the ray gun over said powder bed for the formation of a cross section of said three-dimensional article through fusion of parts of said powder bed, and a controlling computer, in which information is stored concerning consecutive cross sections of the three-dimensional article. A three-dimensional article is formed through consecutive fusions of consecutively formed cross sections of powder layers, successively laid down by the powder dispenser.
Thus, there is a demand for additive manufacturing techniques which are capable of building larger and larger three-dimensional articles. Increasing the build volume also requires higher beam power of the beam power source and/or higher deflection angles of the beam source which may lead to process difficulties in order to keep the beam spot quality equal over the entire build area.